INTERFERENCE OF PARATHION WITH MITOCHONDRIAL BIOENERGETICS

The organophosphorus insecticide parathion depresses the phosphorylation efficiency of mitochondria as inferred from the decrease of RCR and ADP / O ratios. The transmembrane potential (Δψ) developed by energized mitochondria, and depolarization upon ADP addition are also decreased. Furthermore, repolarization is delayed and resumes at a slower rate. The inhibitory action of parathion on phosphorylation efficiency could be related with the following findings: (1) a direct effect on the succinate dehydrogenase-ubiquinone segment of the redox chain; (2) a direct action on the ATP synthetase complex; (3) partial inhibition of the phosphate transporter. © 1990.